scholarly journals Analysis of SARS-CoV-2 RNA Stability and Infectivity in Oropharyngeal Swab Samples

2021 ◽  
Author(s):  
Markus Neumann ◽  
Marica Grossegesse ◽  
Daniel Bourquain ◽  
Lars Schaade ◽  
Andreas Nitsche
Keyword(s):  
Room Temperature ◽  
Infectious Virus ◽  
Optimal Transport ◽  
Rna Stability ◽  
Genomic Rna ◽  
Sample Storage ◽  
Virus Particles ◽  
Reliable Detection ◽  
Good Sample ◽  
Oropharyngeal Swab

Abstract The reliable detection of SARS-CoV-2 genomic RNA and infectious virus particles from patient samples requires a good sample quality. This is especially critical when the sample has to be transported to the analysing laboratory which can take several days. To determine optimal transport conditions, we simulated oropharyngeal swab samples using defined virus amounts and stored the samples at 4 °C or at room temperature for up to four days. Moreover, we analysed the influence of dry swabs in comparison to swabs stored in transport medium. Our results show that care should be taken when analysing samples for infectious SARS-CoV-2 particles since infectivity is strongly influenced by sample storage.

scholarly journals Analysis of SARS-CoV-2 RNA Stability and Infectivity in Oropharyngeal Swab Samples

2021 ◽  
Author(s):  
Markus Neumann ◽  
Marica Grossegesse ◽  
Daniel Bourquain ◽  
Lars Schaade ◽  
Andreas Nitsche
Keyword(s):  
Room Temperature ◽  
Infectious Virus ◽  
Optimal Transport ◽  
Rna Stability ◽  
Genomic Rna ◽  
Sample Storage ◽  
Virus Particles ◽  
Reliable Detection ◽  
Good Sample ◽  
Oropharyngeal Swab

Abstract The reliable detection of SARS-CoV-2 genomic RNA and infectious virus particles from patient samples requires a good sample quality. This is especially critical when the sample has to be transported to the analysing laboratory which can take several days. To determine optimal transport conditions, we simulated oropharyngeal swab samples using defined virus amounts and stored the samples at 4 °C or at room temperature for up to four days. Moreover, we analysed the influence of dry swabs in comparison to swabs stored in transport medium. Our results show that care should be taken when analysing samples for infectious SARS-CoV-2 particles since infectivity is strongly influenced by sample storage.

scholarly journals RNA and Protein Requirements for Incorporation of the Pol Protein into Foamy Virus Particles

2005 ◽  
Vol 79 (11) ◽  
pp. 7005-7013 ◽  
Author(s):  
Katrin Peters ◽  
Tatiana Wiktorowicz ◽  
Martin Heinkelein ◽  
Axel Rethwilm
Keyword(s):  
Foamy Virus ◽  
Genomic Rna ◽  
Rna Packaging ◽  
Gag Protein ◽  
Protein Precursor ◽  
Protein Requirements ◽  
Virus Particles ◽  
Foamy Viruses ◽  
Protein Incorporation ◽  
The Individual

ABSTRACT Foamy viruses (FVs) generate their Pol protein precursor molecule independently of the Gag protein from a spliced mRNA. This mode of expression raises the question of the mechanism of Pol protein incorporation into the viral particle (capsid). We previously showed that the packaging of (pre)genomic RNA is essential for Pol encapsidation (M. Heinkelein, C. Leurs, M. Rammling, K. Peters, H. Hanenberg, and A. Rethwilm, J. Virol. 76:10069-10073, 2002). Here, we demonstrate that distinct sequences in the RNA, which we termed Pol encapsidation sequences (PES), are required to incorporate Pol protein into the FV capsid. Two PES were found, which are contained in the previously identified cis-acting sequences necessary to transfer an FV vector. One PES is located in the U5 region of the 5′ long terminal repeat and one at the 3′ end of the pol gene region. Neither element has any significant effect on RNA packaging. However, deletion of either PES resulted in a significant reduction in Pol encapsidation. On the protein level, we show that only the Pol precursor, but not the individual reverse transcriptase (RT) and integrase (IN) subunits, is incorporated into FV particles. However, enzymatic activities of the protease (PR), RT, or IN are not required. Our results strengthen the view that in FVs, (pre)genomic RNA functions as a bridging molecule between Gag and Pol precursor proteins.

scholarly journals Isolation of Viable SARS-CoV-2 Virus from Feces of an Immunocompromised Patient Suggesting a Possible Fecal Mode of Transmission

2021 ◽  
Vol 10 (12) ◽  
pp. 2696
Author(s):  
Julie Dergham ◽  
Jeremy Delerce ◽  
Marielle Bedotto ◽  
Bernard La Scola ◽  
Valérie Moal
Keyword(s):  
Kidney Transplantation ◽  
Infectious Virus ◽  
Immunocompromised Patient ◽  
Kidney Transplant Recipient ◽  
Enteric Virus ◽  
Rt Pcr ◽  
Virus Particles ◽  
Severe Diarrhea ◽  
Mode Of Transmission ◽  
Compromised Patients

(1) Background: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) excretion in stools is well documented by RT-PCR, but evidences that stools contain infectious particles are scarce. (2) Methods: After observing a Corona Virus 2019 Disease (COVID-19) epidemic cluster associated with a ruptured sewage pipe, we search for such a viable SARS-CoV-2 particle in stool by inoculating 106 samples from 46 patients. (3) Results: We successfully obtained two isolates from a unique patient with kidney transplantation under immunosuppressive therapy who was admitted for severe diarrhea. (4) Conclusions: This report emphasizes that SARS-CoV-2 is an enteric virus, and infectious virus particles can be isolated from the stool of immune-compromised patients like, in our case, kidney transplant recipient. Immune-compromised patients are likely to have massive multiplication of the virus in the gastrointestinal tract and this report suggests possible fecal transmission of SARS-CoV-2.

scholarly journals The effect of storage conditions on samples for the evaluation of copper status in blesbok (Damaliscus pygargus phillipsi)

2002 ◽  
Vol 73 (3) ◽  
Author(s):  
M. Quan ◽  
M.S. Mulders ◽  
D.G.A. Meltzer
Keyword(s):  
Superoxide Dismutase ◽  
Liquid Nitrogen ◽  
Liver Tissue ◽  
Room Temperature ◽  
Storage Conditions ◽  
Superoxide Dismutase Activity ◽  
Activity Levels ◽  
Sample Storage ◽  
Live Animal ◽  
Jersey Cows

Investigaltions to determine the effect of sample storage on the concentration of copper in liver tissue and on the activity of erythrocyte superoxide dismutase were undertaken in preparation for a study of blesbok (Damaliscus pygargus phillipsi) that were suspected to be suffering from copper deficiency. Two liver samples were collected from each of 20 culled blesbok in a manner that simulated the collection of biopsies from the live animal. These samples were stored either in 10 % formalin or frozen at -20 °C until analysed 4 1/2 months later. The effect of different methods of sample storage on superoxide dismutase activity was determined. Erythrocytes collected from 3 Jersey cows and 5 culled blesbok were washed and divided into 0.5m portions, stored at room temperature (~20 °C), in a refrigerator (4 °C), frozen at -20 °C in a freezer, and in liquid nitrogen (-200 °C). An analysis of superoxide dismutase activity was undertaken using a commercial assay kit at intervals of 2-4 days until the levels of activity had fallen significantly. The copper concentration in formalin-preserved liver samples was significantly lower than that measured in frozen liver tissue apparently as a result of leaching. The activity of superoxide dismutase in cattle blood was unchanged for 4 days at room temperature but fell appreciably after 2 days at 4 °C and -20 °C. Enzyme activity remained unchanged for 200 days in erythrocytes stored in liquid nitrogen. Superoxide dismutase activity levels in healthy blesbok were considerably lower than those measured in Jersey cows and remained unaffected for up to 6 days in samples stored at 4 °C and 20 °C. The level of activity fell significantly thereafter. Samples stored in liquid nitrogen were unchanged after 40 days.

scholarly journals STRUCTURE OF TYPE 5 ADENOVIRUS

1963 ◽  
Vol 118 (2) ◽  
pp. 295-306 ◽  
Author(s):  
Wesley C. Wilcox ◽  
Harold S. Ginsberg
Keyword(s):  
Virus Particle ◽  
Density Gradient ◽  
Infectious Virus ◽  
Relative Proportion ◽  
Specific Antigen ◽  
Equilibrium Density ◽  
Virus Particles ◽  
Infected Cells ◽  
Specific Antigens ◽  
Virus Antigens

Type 5 adenovirus was purified by fluorocarbon (freon 113) treatment followed by banding in a CsCl equilibrium density gradient. This method permitted separation of virus from normal host cell materials and virus-specific soluble antigens. Virus banded in CsCl with a mean bouyant density of 1.3349 gm/cm3. The three virus-specific soluble antigens (group- and type-specific antigens and toxin) banded together with a mean bouyant density of 1.2832 gm/cm3. The group-specific antigen was the predominant antigen of the purified virus particle, whereas the group- and type-specific antigens were present in equal titers in the antigen band. Infectious virus particles were inactivated by prolonged dialysis at pH 10.5. Centrifugation of inactivated virus preparations in a CsCl equilibrium density gradient resulted in separation of virus DNA from specific antigen: the antigens banded with a mean bouyant density of 1.2832 gm/cm3 and the DNA sedimented to the bottom of the tube. The predominant antigen derived from purified virus particles was the group-specific antigen and it was in the same relative proportion to the type-specific antigen as measured in intact particles. The antigens derived from disrupted virus were immunologically identical with the soluble virus antigens present in infected cells.

scholarly journals Abundant Defective Viral Particles Budding from Microglia in the Course of Retroviral Spongiform Encephalopathy

2000 ◽  
Vol 74 (4) ◽  
pp. 1775-1780 ◽  
Author(s):  
Regine Hansen ◽  
Stefanie Czub ◽  
Evi Werder ◽  
Jens Herold ◽  
Georg Gosztonyi ◽  
...  
Keyword(s):  
Infectious Virus ◽  
Protein Translocation ◽  
Neuronal Damage ◽  
Ex Vivo ◽  
Spongiform Encephalopathy ◽  
Microglia Cell ◽  
Virus Particles ◽  
Viral Particles ◽  
Type C ◽  
Retroviral Infections

ABSTRACT A pathogenetic hallmark of retroviral neurodegeneration is the affinity of neurovirulent retroviruses for microglia cells, while degenerating neurons are excluded from retroviral infections. Microglia isolated ex vivo from rats peripherally infected with a neurovirulent retrovirus released abundant mature type C virions; however, infectivity associated with microglia was very low. In microglia, viral transcription was unaffected but envelope proteins were insufficiently cleaved into mature viral proteins and were not detected on the microglia cell surface. These microglia-specific defects in envelope protein translocation and processing not only may have prevented formation of infectious virus particles but also may have caused further cellular defects in microglia with the consequence of indirect neuronal damage. It is conceivable that similar events play a role in neuro-AIDS.

scholarly journals Biological Cloth Face Coverings - The Reduction of SARS-CoV-2 and Influenza (H1N1) Infectivity by ViruferrinTM Treatment

2021 ◽  
Author(s):  
Emily Medina Magues ◽  
Anna Stedman ◽  
Paul Hope ◽  
Jorge E. Osorio
Keyword(s):  
Influenza A ◽  
Infectious Virus ◽  
Positive Control ◽  
Influenza A Viruses ◽  
Virus Particles ◽  
Significant Difference ◽  
Untreated Material ◽  
Fabric Material ◽  
Influenza H1n1 ◽  
Time Point

Fabric material was coated with Viruferrin™ and tested for its inactivating properties against the pandemic severe acute respiratory syndrome 2 (SARS-CoV-2) and influenza A viruses. A statistically significant (p<0.0001) decrease in the number of infectious virus particles exposed to Viruferrin-treated fabric when compared with the cotton control for both SARS-CoV-2 and influenza A viruses was observed. For both SARS-CoV-2 and influenza A, Viruferrin-treated fabrics experienced a > 99% virus reduction without saliva after five minutes of contact when compared to the positive control at time point 0. Furthermore, the reusability of the Viruferrin treated fabric was demonstrated by stability for up to 10 washes. The level of anti-viral (SARS-CoV-2) activity remained constant from 5 to 10 washes and demonstrated a significant difference (p<0.0001) from the unwashed untreated material. Applications for this treated fabric are far-reaching, and as a biological face covering offers not only a unique 2-way protection but also is unlikely to cause onward touch transmission.

scholarly journals STUDIES ON HOST-VIRUS INTERACTIONS IN THE CHICK EMBRYO-INFLUENZA VIRUS SYSTEM

1955 ◽  
Vol 101 (5) ◽  
pp. 493-506 ◽  
Author(s):  
Kurt Paucker ◽  
Werner Henle
Keyword(s):  
Influenza Virus ◽  
Infectious Virus ◽  
Allantoic Fluid ◽  
Progressive Reduction ◽  
Virus Particles ◽  
Host Virus Interactions ◽  
Virus Interactions ◽  
Available Information ◽  
Virus System

An experimental analysis is here presented of the conditions that lead to the appearance of non-infectious hemagglutinins (NIHA) in the allantoic fluid of chick embryos injected with standard influenza virus (PR8 strain) which had been exposed to 37°C. in vitro for various periods of time. On progressive reduction of the infectivity of the undiluted inocula from about 109 to 103 ID50 (103.2 HA units) the yields of infectious virus in 24 hours decreased in straight correspondence 1 millionfold, but those of hemagglutinins only by a factor of 10. Thus the proportions of NIHA in the yields increased sharply but the total quantity obtained decreased gradually. The quantities of infectious virus produced per ID50 injected were the same throughout this range; i.e., between 50 and 100 ID50, regardless of increasing proportions of heat-inactivated virus in the seeds. This value agrees with previous estimates of yields under other conditions. Thus, initiation and completion of first cycles by the infectious virus remaining in the inocula were not, or at most, slightly inhibited. The inactivated virus, therefore, failed to establish immediate interference. It was capable, however, of holding the infectious process to one cycle. Upon 10-fold dilution of the seeds essentially similar results were obtained except that a slight loss in interfering activity could now be detected with an increase in exposure to 37°C. With further dilutions little or no interference was noted. The capacity to yield NIHA decreased slowly during exposure of the seeds to 37°C. over a period of 5 days, thereafter more rapidly. It could not be restored by addition of infectious virus. Furthermore, since NIHA was obtained when the seeds contained as little as 102 or 103 ID50, it is unlikely that it was derived from those cells which had adsorbed both infectious and inactivated seed virus. It is suggestive that multiple adsorption of inactivated virus particles per se will yield NIHA. The available information, as discussed, favors the view that the NIHA does not represent seed virus in some form but is newly produced.

scholarly journals Retroviral Env Glycoprotein Trafficking and Incorporation into Virions

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Tsutomu Murakami
Keyword(s):  
Infectious Virus ◽  
Structural Data ◽  
Host Factors ◽  
Structural Protein ◽  
Gag Protein ◽  
Virus Particles ◽  
Virion Incorporation ◽  
Actual Mechanism ◽  
Env Protein ◽  
Env Glycoprotein

Together with the Gag protein, the Env glycoprotein is a major retroviral structural protein and is essential for forming infectious virus particles. Env is synthesized, processed, and transported to certain microdomains at the plasma membrane and takes advantage of the same host machinery for its trafficking as that used by cellular glycoproteins. Incorporation of Env into progeny virions is probably mediated by the interaction between Env and Gag, in some cases with the additional involvement of certain host factors. Although several general models have been proposed to explain the incorporation of retroviral Env glycoproteins into virions, the actual mechanism for this process is still unclear, partly because structural data on the Env protein cytoplasmic tail is lacking. This paper presents the current understanding of the synthesis, trafficking, and virion incorporation of retroviral Env proteins.

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